It might not be "necessary" for a website dedicated to salt shakers, but if I can provide my users privacy when reading my site(unencrypted DNS notwithstanding), why wouldn't I? It should be a common courtesy. While I'm browsing the web, I should expect that nobody but the host can tell what it is that I'm doing.

> It will also prevent older computers from accessing the web as ssl standards evolve, which is kind of a shame.

At what point should an older computer no longer work with the current web? Eventually there's going to be a breaking change. A computer old enough that its browser can't be updated is probably vulnerable to all sorts of browser-based attacks.